Nebulizers are known in which preheated water is driven in a thin stream against a target so as to break up into small particles which mix with the surrounding air in order to moisturize same. Other systems use ultrasonic vibrations to fragmentize the water stream. It is generally desired to make the particle size as small as possible, preferably of 5 microns or less, so as to facilitate penetration of the water particles into the respiratory tract of a patient. However, the mist produced in this manner is not very stable since the water particles are not uniformly dispersed in the airflow and tend to coalesce, thereby forming larger droplets which settle out prematurely in the supply conduit as well as in the respiratory tract itself. The equipment is relatively inefficient, complex and correspondingly expensive, especially for home use; moreover, unless the water is preboiled, sterile conditions are difficult to maintain.
In U.S. Pat. No. 3,894,537, I have described an effective steam-air inhalator which gives very satisfactory results. My copending application Ser. No. 868,569 filed Jan. 10, 1978 is an improvement over this patent in that provision is made for incorporating medication in moist air, or oxygen, or oxygen-rich air and also for returning condensate to the steam generator. Both said patent and application are incorporated herein by reference.
It is a general object of this invention to provide an improved inhalator for producing a stable mist of submicron particles wherein the temperature of said mist can be varied.
A further object is to provide a means to vary the direction of a portion of a pressurized gas stream exiting a venturi tube to vary the vacuum produced in a venturi.